package org.bouncycastle.jce;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.security.cert.CRLException;
import java.security.cert.CertificateEncodingException;
import java.security.cert.X509CRL;
import java.security.cert.X509Certificate;

import org.bouncycastle.asn1.ASN1InputStream;
import org.bouncycastle.asn1.ASN1Sequence;
import org.bouncycastle.asn1.x509.TBSCertList;
import org.bouncycastle.asn1.x509.TBSCertificateStructure;

/**
 * a utility class that will extract X509Principal objects from X.509 certificates.
 */
public class PrincipalUtil {
    /**
     * return the issuer of the given cert as an X509PrincipalObject.
     */
    public static X509Principal getIssuerX509Principal(X509Certificate cert) throws CertificateEncodingException {
        try {
            ByteArrayInputStream bIn = new ByteArrayInputStream(cert.getTBSCertificate());
            ASN1InputStream aIn = new ASN1InputStream(bIn);
            TBSCertificateStructure tbsCert = new TBSCertificateStructure((ASN1Sequence) aIn.readObject());

            return new X509Principal(tbsCert.getIssuer());
        } catch (IOException e) {
            throw new CertificateEncodingException(e.toString());
        }
    }

    /**
     * return the subject of the given cert as an X509PrincipalObject.
     */
    public static X509Principal getSubjectX509Principal(X509Certificate cert) throws CertificateEncodingException {
        try {
            ByteArrayInputStream bIn = new ByteArrayInputStream(cert.getTBSCertificate());
            ASN1InputStream aIn = new ASN1InputStream(bIn);
            TBSCertificateStructure tbsCert = new TBSCertificateStructure((ASN1Sequence) aIn.readObject());

            return new X509Principal(tbsCert.getSubject());
        } catch (IOException e) {
            throw new CertificateEncodingException(e.toString());
        }
    }

    /**
     * return the issuer of the given CRL as an X509PrincipalObject.
     */
    public static X509Principal getIssuerX509Principal(X509CRL crl) throws CRLException {
        try {
            ByteArrayInputStream bIn = new ByteArrayInputStream(crl.getTBSCertList());
            ASN1InputStream aIn = new ASN1InputStream(bIn);
            TBSCertList tbsCertList = new TBSCertList((ASN1Sequence) aIn.readObject());

            return new X509Principal(tbsCertList.getIssuer());
        } catch (IOException e) {
            throw new CRLException(e.toString());
        }
    }
}
